Plant-Insect Ecosystems
10-Minute Paper
Rehan Arshad
Graduate Research Assistant
University of Georgia
Griffin, Georgia
Systena frontalis (F.) (Coleoptera: Chrysomelidae) is a serious insect pest of ornamental plants in container nurseries in the central and eastern USA. Adults of S. frontalis feed on the leaves and cause numerous shot holes on young and mature foliage, which are not marketed. In spring, S. frontalis adults were observed on many host plants in nurseries. The potting media of plant containers could be a potential overwintering site of S. frontalis, but this is not systematically determined. Thus, the study aimed to determine if potting media of containers serve as a potential overwintering site for immatures of S. frontalis in nurseries. Experiments were conducted on panicle hydrangea (Hydrangea paniculata Siebold) in Georgia, North Carolina, and Virginia nurseries in 2021 and 2022. The treatments of the experiments were: 1) canopy caged, 2) whole plant caged, and 3) noncaged hydrangea plants. The adult densities and feeding damage were recorded. Overall, the numbers of adult S. frontalis found on the foliage were significantly greater for the fully caged and noncaged treatments than for the caged canopy treatment. The incidence and severity of S. frontalis feeding damage were significantly greater for the fully caged and noncaged treatments than for the caged canopy treatment. This suggests that high numbers of S. frontalis adults consistently emerged from the potting media of the plant container overwintered in the nurseries. Because plant containers can harbor large numbers of S. frontalis during winter, control measures targeting overwintering immature populations in potting media may reduce adult damage in spring.